I saw that thread but I did miss this quote from Mammut via 'hascoituswithursa'

bearbreeder wrote:

heres the response from dead elephant Hello (name deleted by me),

you had a question on your Mammut rope Phoenix 8mm and whether it can be used in twin and half rope technique in one single pitch. This is the case, you can always clip the two rope strands as twins, then split them as doubles, join again etc. This is exactly the advantage of half ropes compared to twin ropes where you always need to clip both ropes.

Tend to disagree. Twins as twins through the whole pitch! Doubles as doubles through the whole pitch! Reason being is that twins are clipped though every binner on the pitch, so if you fall both ropes move as one. On double rope lead left rope is clipped through it's own running belay and the right rope is clipped through it's own running belay. When you fall the left and right ropes move at different speeds and stretch at different rates. Possibility of one rope burning through the other if you mix and match twin technique with double technique.

Just because people have mixed the techniques doesn't make it the safest. Law of averages say you'll probably be o.k. if you do but it's the one time that it's not o.k. that counts.

well personally id rather trust the manufacturer than some random RCer

which is why i asked them directly rather than going through the RC "yur gonna die" gongshow

i would think mammut would know what they are doing after 151 years in the climbing business

Hello (deleted),

you had a question on your Mammut rope Phoenix 8mm and whether it can be used in twin and half rope technique in one single pitch. This is the case, you can always clip the two rope strands as twins, then split them as doubles, join again etc. This is exactly the advantage of half ropes compared to twin ropes where you always need to clip both ropes.

Rope on rope friction is the leading argument for not joining ropes after they have been separated. The Dano case is totally different though. In other to get a significant difference in stretch between the 2 ropes, one of them would need serious drag. In that case you wouldn't be clipping it. Furthermore the ropes would need to slide of over the other.

These are the 2 theories. Until I found the email from Mammut. One statement but from a reputable source. Does anyone have a test or study to the contrary. There are a couple of blogs but again I think this is more theory than actual data.

Guess you could say I'm some random RCer. Been climbing most of my life and despite what a given manufacturer says about a product or it's use I'll go with my gut instinct and my climbing experience to err on the side of safety. Especially when the gain is minimal as in the mixing of twin and double technique. What you gain and the possibility of failure are yours to choose.

Personally I rarely climb on twins or doubles. Just go with a single lead with a thin tag but I understand both techniques and have climb with people who use both.

You can start out using them as twins and then separate to halves, but do not join them back to twins once separated unless you use two different slings and biners. The problems is that once you separate the ropes, the amount of rope out for each strand and the amount of drag for each strand is different. Accordingly, when you fall the ropes can move at different speeds, which if allowed to contact each other could result in rope damage.

well personally id rather trust the manufacturer than some random RCer

which is why i asked them directly rather than going through the RC "yur gonna die" gongshow

i would think mammut would know what they are doing after 151 years in the climbing business

Hello (deleted),

you had a question on your Mammut rope Phoenix 8mm and whether it can be used in twin and half rope technique in one single pitch. This is the case, you can always clip the two rope strands as twins, then split them as doubles, join again etc. This is exactly the advantage of half ropes compared to twin ropes where you always need to clip both ropes.

The guy that replied is likely just some grunt from marketing. If you spoke to the senior R&D engineer for Mammut I bet he would tell you something different. Send an e-mail to both Bluewater and Sterling, ask to speak to an engineer, then ask the question again. I bet you will get a different answer.

You can start out using them as twins and then separate to halves, but do not join them back to twins once separated unless you use two different slings and biners. The problems is that once you separate the ropes, the amount of rope out for each strand and the amount of drag for each strand is different. Accordingly, when you fall the ropes can move at different speeds, which if allowed to contact each other could result in rope damage.

I'll play devil advocate. There IS different rope drag for each rope but how much is the question. If able to split and combine at will the rope drag will be significantly reduced. How much is too much if it's even applicable? Then the ropes are BOTH passing through the biner, so it's not like one is stationary and the other passing over a single point at high speed. The weighted rope will most likely go to the bottom of the biner.

It's all conjecture though. I have believed as you for many years but with the new 7.8mm ropes out I'm looking deeper into it and finding surprisingly little in terms of actual data.

You are quite right about starting them as twins and not rejoining them once they are split. The reason you would use doubles is to reduce rope drag as much as possible. Each double rope is rated for falls on it's own. So by clipping them together you lose a bit and for what gain?

The guy that replied is likely just some grunt from marketing. If you spoke to the senior R&D engineer for Mammut I bet he would tell you something different. Send an e-mail to both Bluewater and Sterling, ask to speak to an engineer, then ask the question again. I bet you will get a different answer.

product managers are required to know all the ins and outs of their products and the uses ... its not simply a marketing position

you can see the depth of their USA product manager here ... i bet he knows more than you on ropes

You can start out using them as twins and then separate to halves, but do not join them back to twins once separated unless you use two different slings and biners. The problems is that once you separate the ropes, the amount of rope out for each strand and the amount of drag for each strand is different. Accordingly, when you fall the ropes can move at different speeds, which if allowed to contact each other could result in rope damage.

I'll play devil advocate. There IS different rope drag for each rope but how much is the question. If able to split and combine at will the rope drag will be significantly reduced. How much is too much if it's even applicable? Then the ropes are BOTH passing through the biner, so it's not like one is stationary and the other passing over a single point at high speed. The weighted rope will most likely go to the bottom of the biner.

It's all conjecture though. I have believed as you for many years but with the new 7.8mm ropes out I'm looking deeper into it and finding surprisingly little in terms of actual data.

This is a difficult question because it is like asking how many falls are required before a rope truly becomes unsafe. The answer is it depends. If you went a full pitch not clipping a half at all and then clipped both ropes as a twin on the last piece, then took a 50 footer on it, I bet something bad would happen. But if you clipped the first piece as a half, then used twins for the rest of the pitch and fell at the end of the pitch, I strongly doubt anything would happen.

It's really a variable question with a variable answer. But it is kind of a pointless question because who the hell climbs a pitch using twins, then halves, then twins, then halves and on and on? Once you switch out to halves there normally isint much of a need to use the twin method, except maybe while climbing over a ledge, in which case just use two separate draws and clip the rope as a twin. Problem (mostly) solved.

The guy that replied is likely just some grunt from marketing. If you spoke to the senior R&D engineer for Mammut I bet he would tell you something different. Send an e-mail to both Bluewater and Sterling, ask to speak to an engineer, then ask the question again. I bet you will get a different answer.

product managers are required to know all the ins and outs of their products and the uses ... its not simply a marketing position

you can see the depth of their USA product manager here ... i bet he knows more than you on ropes

remember that unlike RCers saying whatever they want, "safe" usage directions from a manufacturer such as mammut carries LIABILITY

Sure. I mean, its not like I work in the industry and climb with these said marketing guys and engineers or anything. As far as climbing hard, I have climbed grade V 5.12+ and multiple lines on El Cap--that's plenty hard enough. And only a Sharma stocker would actually think that climbing 5.14 gives you an engineering-level understanding of climbing gear. I know because I have climbed with a large sum of them. Some of them dont really know jack outside of how to dyno to a mono.

I am not saying that Mammut's staff are unqualifed. I am sure they all know a ton about climbing. But I have also spoken to Petzl employees that dont know their own Dragonfly rope is not UIAA certified as a twin, and Black Diamond employees that do not know that their pins are made out of chrome molybdenum steel, and the list goes on and on. Hell, the CEO of Sterling ropes isint even a rock climber (not that she needs to be, but one would assume)! So my point is not everyone knows everything about every subject and if a bunch of people are saying something other than what you think the correct answer is, you would be well off to further inquire using many references and sources instead of blindly believing the reference that best supports your opinion is gold.

Look, of course there have been climbers who have rejoined their halves and fallen on them without issue. Safety is a sliding scale. "Safe or not" is a question of your personal risk assumption. I am absolutely positive, no matter how many marketing guys say otherwise, that I could create a system in which you could get enough rope speed difference between the two ropes to cause a problem. I have blazed the sheath of a rope solely from the friction of a carabiner while taking a big space whipper. So if the carabiner alone can damage a sheath from friction, then two ropes in that carabiner, each moving at a different speed, certainly can cause problems under some conditions. Few people realize just how sensitive nylon is to heat (350F causes major strength loss) and how fast a rope can heat up under heavy friction while rubbing against other nylon components. I have seen a climber melt through the sheath of his rope, exposing the core, on a small lead fall because his tag line got caught in the lead line and rubbed against it during the fall. Crap happens.

Sure. I mean, its not like I work in the industry and climb with these said marketing guys and engineers or anything. As far as climbing hard, I have climbed grade V 5.12+ and multiple lines on El Cap--that's plenty hard enough. And only a Sharma stocker would actually think that climbing 5.14 gives you an engineering-level understanding of climbing gear. I know because I have climbed with a large sum of them. Some of them dont really know jack outside of how to dyno to a mono.

I am not saying that Mammut's staff are unqualifed. I am sure they all know a ton about climbing. But I have also spoken to Petzl employees that dont know their own Dragonfly rope is not UIAA certified as a twin, and Black Diamond employees that do not know that their pins are made out of chrome molybdenum steel, and the list goes on and on. Hell, the CEO of Sterling ropes isint even a rock climber (not that she needs to be, but one would assume)! So my point is not everyone knows everything about every subject and if a bunch of people are saying something other than what you think the correct answer is, you would be well off to further inquire using many references and sources instead of blindly believing the reference that best supports your opinion is gold.

Look, of course there have been climbers who have rejoined their halves and fallen on them without issue. Safety is a sliding scale. "Safe or not" is a question of your personal risk assumption. I am absolutely positive, no matter how many marketing guys say otherwise, that I could create a system in which you could get enough rope speed difference between the two ropes to cause a problem. I have blazed the sheath of a rope solely from the friction of a carabiner while taking a big space whipper. So if the carabiner alone can damage a sheath from friction, then two ropes in that carabiner, each moving at a different speed, certainly can cause problems under some conditions. Few people realize just how sensitive nylon is to heat (350F causes major strength loss) and how fast a rope can heat up under heavy friction while rubbing against other nylon components. I have seen a climber melt through the sheath of his rope, exposing the core, on a small lead fall because his tag line got caught in the lead line and rubbed against it during the fall. Crap happens.

so mister RC "expert"

let me ask you this, how much TESTING have you done one mammut ropes, perhaps you can share with us the results

here you are slagging the mammut product managers .. perhaps you can share with us YOUR particular expertise with their rope products ... which so confidently leads you to proclaim that they are wrong with the usage of THEIR products

here you are bragging about el cap, 5.12, etc again ... but how much do YOU use and whip on halves in such a configuration

you arent putting down mammut on lack of REAL experience with the product in such a setup would you

Sorry for the late response to your question. I was away on a short climbing vacation with my family.

So thenÖ

Indeed there has been lots of discussion on this topic and a pretty wide range of thoughts and opinions. Unfortunately the UIAA (the international mountaineering standards writing organization) does not clarify this point very well in the standard document. The standard, UIAA 101 (EN 892) merely states that a rope certified as half is suitable for use in pairs and clipped separately while a rope certified as twin is suitable for use in pairs and must be clipped together into the same carabiner as though they were a single rope. Currently there is no mention of how the ropes should be treated when it has a dual certification.

My personal opinion, as rope engineer and a climber, is that one should choose one technique before starting each pitch and stick with it to the end. Changing the technique back and forth mid pitch would likely create situations where the ropes have the possibility running unevenly (speeds) or even in opposite directions in the event of a fall. This could cause, as you stated, the potential for rope on rope friction, which we know can cause damage to the nylon. While Iíve never heard of a rope failure from such a scenario I see it as one possibility that can easily be avoided by sticking with one technique per pitch. That said, in 35+ years of climbing, and a huge amount of that time with half ropes and twin ropes, Iím certain I have mixed the techniques mid pitch many times without incident. I believe the point Iím trying make here, is to go with the best practices first but when thatís not possible you have to go with what works.

I know this does not clarify the issue much beyond your previous understanding but I hope it helps you make wise choices while you climb. If I can be of any further help feel free to contact me.

Best regards,

Jim

Jim Ewing Product Engineer Sterling Rope Company, Inc.

I also ask if he could do a non official test.

Jim Ewing wrote:

Iíve been trying to imagine some sort of test set up for this issue in years past but it never seems to become a very high priority, unfortunately. If you have some ideas feel free to share them and Iíll try to determine if it is possible to set up a test.

You can start out using them as twins and then separate to halves, but do not join them back to twins once separated unless you use two different slings and biners. The problems is that once you separate the ropes, the amount of rope out for each strand and the amount of drag for each strand is different. Accordingly, when you fall the ropes can move at different speeds, which if allowed to contact each other could result in rope damage.

The "rule" against nylon on nylon contact is meant to prevent a scenario where a running rope crosses a fixed non-moving rope or sling, under load. The friction imparted to the fixed nylon piece can quickly melt through that piece--and this has been well documented.

The situation posed here, however, is quite unlike that. Frankly, I can't envision any scenario where one of the two ropes, upon being separated and then rejoined, would cross the other rope with either of the two ropes being fixed and not moving. As long as both ropes are moving (same direction and different speeds, or different directions) I don't see any problem.

Nylon on nylon contact under load is not always bad, per se. If that were true, Munter hitch belays would be uniformly fatal--and of course, they are not.

You can start out using them as twins and then separate to halves, but do not join them back to twins once separated unless you use two different slings and biners. The problems is that once you separate the ropes, the amount of rope out for each strand and the amount of drag for each strand is different. Accordingly, when you fall the ropes can move at different speeds, which if allowed to contact each other could result in rope damage.

The "rule" against nylon on nylon contact is meant to prevent a scenario where a running rope crosses a fixed non-moving rope or sling, under load. The friction imparted to the fixed nylon piece can quickly melt through that piece--and this has been well documented.

The situation posed here, however, is quite unlike that. Frankly, I can't envision any scenario where one of the two ropes, upon being separated and then rejoined, would cross the other rope with either of the two ropes being fixed and not moving. As long as both ropes are moving (same direction and different speeds, or different directions) I don't see any problem. Nylon on nylon contact under load is not always bad, per se. If that were true, Munter hitch belays would be uniformly fatal--and of course, they are not.

the relevant worry IMO is the difference in rope STRETCH between the two strands ... if you take falls on halves, IME this is fairly minimal ... of course i dont take a ton of whippers on halves at the full 70m rope length, but i doubt most RCer have such experiences either ...

on a perfectly vertical crack, ive noticed half ropes tend to overlap one another regardless, even with alternate clipping ... "burning" through should be as much a worry

a pic from UK climbing

the other thing to keep in mind is that different manufacturers will have different opinions on the use of a similar product ... for example all mammut half ropes are cleared for twin use, have been for years even though they were never officially rated as such till recently ... while other manufacturers will say its a no-no even though their halves have a lower impact force than the mammuts

then theres the famous DMM and dyneema issue .. while metolius goes and sells a dyneema PAS

IMO there are things that will likely kill you ... using halves and twins techniques in the same pitch aint one of them, just like the fear of crossloaded belay biners and the attempts to "solve" it

as you said, if we did worry about it, no one should use the munter

if anyone has any real testing, i would happy to contact mammut again and ask for their opinion ...

Iíve been trying to imagine some sort of test set up for this issue in years past but it never seems to become a very high priority, unfortunately. If you have some ideas feel free to share them and Iíll try to determine if it is possible to set up a test.

I could imagine a test jig that would be easy to incorporate into a standard drop test tower, something like this...

This should allow the two ropes to stretch at differing speeds/amounts. Any wear would be witnessed where the ropes pass through the top combining "biner".

I think in your case the speed differential at the top anchor is minimal if you take a standard fall. If the fall is huge or if the climber continues higher placing more pro and then that will increase the speed differential.

I think the highest rubbing will occur at T1 not T final The more you place L1 & L2 to the left the more rope drag is created. In that case I wouldn't clip rope L until pro T2 or T3 even.